


Intoxication

by SStar



Category: Sherlock (TV), Sherlock Holmes & Related Fandoms
Genre: Alpha Mycroft, Alpha/Beta/Omega Dynamics, Alternate Universe - Gender Changes, Community: sherlockbbc_fic, F/M, Female Sherlock Holmes, First Time, Genderswap, Omega Sherlock, Omega Verse, POV Mycroft Holmes, Plot What Plot/Porn Without Plot, Sex Toys, Sibling Incest, holmescest
Language: English
Status: Completed
Published: 2014-04-11
Updated: 2014-04-16
Packaged: 2018-01-19 01:01:53
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 5,307
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1449502
Author URL: https://archiveofourown.org/users/SStar/pseuds/SStar
Summary: <blockquote class="userstuff">
              <p>Sherlock likes to win and she’s not above cheating. At that moment Mycroft knows he’s lost but he’s still not prepared when Sherlock reveals the hand she’s kept hidden behind her. She’s holding up the toy, a pale-lilac coloured vibrator, the one she had inside her not a minute ago and is coated in Sherlock’s scent. And he watches as she raises it to his face, teasing movements near his mouth, just under his nose, and all his senses are overwhelmed by Sherlock.</p><p>From the <a href="http://sherlockbbc-fic.livejournal.com/21766.html?thread=129781766#t129781766">sherlockbbc_fic kink meme prompt</a>: Omega!Sherlock lives with her older brother, Alpha!Mycroft, in Central London. She comes in particularly heavy that month, and the hormones drive Mycroft insane.</p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

> Disclaimer: all characters belong to ACD, Moffat, Gatiss and the BBC. I own nothing but my own filthy mind.
> 
> Unbeta'd but edited - all mistakes are my very own.

The car has barely come to a stop outside of his home when Mycroft is opening his passenger door and getting out, relief filling him at finally being able to stand on his own two feet. After nearly three hours on the road driving back from the monthly off-site meeting, held this month in the city of Bristol, Mycroft indulges in his need to stretch his body, all six foot one inches of it. He waits, impatiently, as his driver pulls his overnight bag and briefcase from the boot and hands them over. He gives the man a quick nod of dismissal and turns, long legs making quick work of the short path to his front door, before the car engine has even started. Though to be fair, at twenty to midnight most people could excuse Mycroft his reluctance to dally, to stay out in the brisk and cold of this inky black night.

Seconds later, the front door is locked behind him and his overnight bag and briefcase set down next to the hallway table. Mycroft can’t hold back a yawn and the crack of his jaw sounds like a gunshot in the quiet of the house. He blinks rapidly and even shakes his head in an attempt to clear the fuzzy feeling from his mind before listening for any signs of life.

He presumes his sister is out for the night, perhaps on a case, or is already asleep. Neither option would surprise him the night following her heat.

A sudden flash of memory penetrates the drowsiness that’s settling upon him and he dives into his overnight bag and pulls out a small gift-bag, leaves it on a small side table where he knows his sister will find it the next day. The little bag, a monthly occurrence, always includes a pack of tampons, a blister pack of painkillers he knows Sherlock prefers and a box of the gourmet Belgian chocolates she always craves, even as she claims her body is mere transport.

After all he might be a man, an alpha and the British Government but he knows better than to cross his omega sister just after her heat and during her period. It was why he had initiated the off-site meetings – held each month in a different British city. Mycroft has been predicting his little sister’s heats for years; every month, right on schedule, his car picks him up at five in the morning and he returns late the following night once his sister’s heat had passed. Rarely does he need to tweak his schedule and he’s thankful that Sherlock’s body is as habitual about her heats as she is about her experiments. If he ignores the small fact that he’s had to replace his _entire_ range of tableware at least once each year and has had to refurbish his kitchen twice.

And Mycroft found himself relieved that this month’s trip to Bristol hadn’t needed any rescheduling otherwise he’s sure he would _still_ be listening to the whining of the Secretary of State for Health at how the meeting would have clashed with– Mycroft ruthlessly cuts the pointless train of thought off, not wanting to imagine what nonsense the politician actually got up to in his free time. Why the man thought he could whine at Mycroft of all people was a little baffling but he’s sure that the plan Andrea has in play will stop the man from harassing him soon enough.

As he trudges up the stairs to his own bedroom, Mycroft’s tired mind casts back to the start of the week; of how Sherlock who, always quick to temper especially when faced with idiocy, had been waspish, more so than normal, even with him when he’d simply asked if she’d like a cup of tea. He’d been careful not to draw any attention to the small spots that always seemed to appear on her pale skin at this time or her slightly bloated appearance, a lesson learnt in childhood. He still bears the scars and his mother’s scolding rings in his ears to this day. And he _definitely_ knew better than to voice his deduction that Sherlock had spent the week wandering their home wearing silk tops in an attempt to ease the pain of rough fabric rubbing against sore nipples, surely only a simple and natural result of her body’s reaction to the omega hormones coursing through her body. Still, Mycroft is clever enough to know that speaking this small fact aloud would have resulted in something worse than a couple of scars from sharp fingernails.

As smart as he is, and he knows just how smart he is compared to the ordinary people he has to traverse every day, Mycroft isn’t able to have this rational, science-based conversation with his little sister, who is happy enough to expound upon her latest cases, her chemistry or cadaver experiments with him. And yet every time he attempts to mention her normal reactions to her heat Sherlock snarls at him, heated words and curses fly from her pretty mouth and he finds himself hiding away from her. He’s long come to the realisation that whilst all ordinary people are boring and his little sister who might be slow to him but is not like the other goldfish surrounding them, she, and all the other omegas, fall into the category of _scary-do-not-provoke_ at that time of month and it would be smart to heed that unspoken warning. And Mycroft was always the smartest of them all.

He’s slipping off the last of his clothes as he’s been mulling this over, and Mycroft doesn’t linger on why he’s thinking about his little sister’s monthly heat and periods, his suit is now a creased jumble of fabric on the floor. He’ll have to apologise to his housekeeper when he next sees her but at nearly midnight, all Mycroft wants to do is slip into his comfortable bed and fall sleep. A few minutes later, nightly absolutions complete, he does just that.

 

* * *

 

One moment he’s asleep, dead to the world. And then all of a sudden Mycroft is awake.

In those first few seconds of awareness where his sub-conscious is both aware that he’s safe and sound in his own home and yet still drifting on the cusp of oblivion, his mind feels much like the fog that crowns the top of the buildings in London’s square mile on a cold winter’s day, caught between sleep and wakefulness. A full body shiver wracks his body and he realises why he’s suddenly awake. A glance at his bedside table and he’s irritated to realise he’s only managed to sleep for two hours before being rudely awoken.

With a grumble Mycroft pushes himself out of his warm, welcoming bed and his body shudders again as the cold night air hits warm skin. He grabs his dressing gown and wraps it around him, bare feet curl into the thick, luxurious carpet that cover each room on this floor and swallow up the sound of footsteps. Once he’s in the hallway it takes Mycroft a long moment to identify, and had he had his wits about him he might have paid more attention at the length of time it takes him to make the realisation, why he’s suddenly awake. _Sherlock._ Of course it would be his irritating, self-centred little sister, no one else manages to cause such upheaval, big or small, a minor incident or one that involves the resources available at Five or Six, in his quiet, well-arranged life.

Why Sherlock has suddenly decided to open _all_ the windows in their home at two o’clock in the morning is beyond him. He hurries to each window and closes it, ignoring the goose pimples that rise on his own skin. Mycroft still feels like he’s walking through a fog, blames it on his lack of sleep, and it seems to take an age to get all the windows shut. The idea that his senses, his perception of time, might be off flits through his mind but it slips through a crack before he can grasp it, examine it. His body is still trembling and Mycroft narrows his eyes and tries to focus, as though that will help him to see, to understand, and he _knows_ that all the windows in his room and the hallway are closed.

_Sherlock’s room._

He’s moving again with determined, quick steps. Mycroft thinks – _tries to think_ – as soon as he closes this last errant window he can crawl back into his own bed, and even though he feels warmer now his body is still experiencing soft tremors. _From the window letting in the cold night air obviously_. He hopes he isn’t falling ill; it would be such a terrible waste of a perfectly lovely, lazy weekend.

Mycroft stands at Sherlock’s closed door. He gives a perfunctory knock and he hears a noise from within so he twists the handle to open the door, fully intending on telling his sister off but the words die on his tongue.

In contrast to the rest of the still, dark house, the bedside light lends the room a soft glow, gives Mycroft and his keen, attentive eyes the perfect view. Of his _little sister_ , Sherlock, an omega, on her bed. Naked. Writhing.

_In heat._

He has just enough sense and control to command his hands to grip the doorframe and door-knob but his feet won’t move backwards and his eyes are fixed to the sight on the bed. His calculations had been off. That had never happened before but Mycroft’s rational mind is becoming ever more befuddled, the fog-like feeling creeping all around, immobilising him.

Sherlock hasn’t noticed him, Mycroft realises. She’s too focussed on attending to her own pleasure if the small array of toys on her bed is any indication. He’s never before thought too deeply about how she handles her monthly heats, very deliberately ignored it in the past. He supposes like many other single omegas she either engaged the services of an agency or toys; the former possibility being why he’s always made sure to never stay in their home during her heats. The idea of another alpha in his home is repellent but he doesn’t have to force _that_ thought away when a quick glance at the bed does it for him.

His eyes move over the expanse of creamy skin and long limbs, contrasted against the dark blue bedding, slim fingers that move in and out of sight as Sherlock thrusts her hips against some object – _a toy, perhaps a knotting dildo_ – a distant part of his mind supplies. The sharp angles of the doorframe dig into his trembling fingers as he tightens his grip especially when Sherlock takes a particularly vicious thrust and her head falls back on top her pillow, exposing her long neck, and moans.

Mycroft tries to choke back his own instinctive response, grits his teeth, but his own answering growl echoes in the room.

Sherlock’s head snaps up, although she can’t quite stop her hips moving, and Mycroft locks onto her eyes, blown wide with her heat, with need. He stops breathing, doesn’t move apart from the quaking that’s threatening to take his body over. He knows he should leave but he can’t.

“ _Mycroft_.” A reprimand, supplication and benediction rolled into one.

He’s light-headed all of a sudden before he remembers that he needs to breathe and so he takes a deep gulp of air, two, three, and more. They’re deep, rasping noises that rumble in his chest but he can’t stop that. Mycroft screws his eyes shut but the moving image of his sister thrusting a sex toy into her body is imprinted indelicately in his memory and will be forever more but he _does_ manage to bite back a second growl.

With his eyes shut, his other senses come to the fore and in a flash he’s aware of Sherlock’s scent. It’s all over her bedroom, hangs in the air and Mycroft wonders how he’s missed it until that moment. He catches the rustle of fabric and he prays to a deity he doesn’t believe in that Sherlock has covered up, that he can retain enough control to get back to his room, dress and get out of the house. As it happens Sherlock’s scent instead gets stronger; a primal urge surges, he takes a long, deep sniff and his eyes snap open.

“ _What_ are you doing?” he gasps.

Sherlock is standing in front of him, barely three feet away, is still naked and he can’t look away. Can’t help but scent her.

“It won’t work,” Sherlock gripes, and she’s glaring at him as though this is _his_ fault. “I can’t handle this because your stupid, primitive hormones are muddling with mine.”

“Sherlock, you have to get away,” he bids. “Away from me.”

“Why?”

“Are you really that foolish?” Mycroft snaps back but immediately feels remorse and _something else_ as his sister bites her lush, full lower lip shamelessly. “We _cannot_ do this.”

“But you want to,” Sherlock points out and Mycroft wonders whether there can be a hell if he doesn’t believe in a heaven.

“Hormones,” he grits out. “Purely a biochemical reaction.”

“I don’t mean that!”

“ _Don’t_.” Mycroft drops his head and he realises he’s close to breaking. Or begging. He’s not sure there’s any difference between the two at this moment. “Not here. Not now!”

“You can’t leave me like this,” Sherlock retorts. Her voice is steady, firm and Mycroft wishes he had even a small part of her control right now. But when he looks at his little sister he sees the maelstrom brewing in her expressive blue eyes. He realises she’s not calm, or in control.

Sherlock steps closer to him and Mycroft’s thoughts and desires collide as he watches her warily. _Want. Taboo. Desire. Consent. Comfort. Wrong. Protection. Need. Love._

“I should,” he whispers.

His sister is so close to him now that if he lets go of the door, his fingers could curl into her hips, leave bruises that would last for days, marks of his ownership. He’s distracted by the vision, as desire coils in his gut, for a moment and it’s time enough. She’s looking up at him through thick, dark lashes and there’s that little quirk to her lips he instantly recognises.

Sherlock likes to win and she’s not above cheating. At that moment Mycroft knows he’s lost but he’s still not prepared when Sherlock reveals the hand she’s kept hidden behind her. She’d holding up _the_ toy, a pale-lilac coloured vibrator, the one she had _inside_ her not a minute ago and is coated in Sherlock’s scent. And he watches as she raises it to his face, teasing movements near his mouth, just under his nose, and all his senses are overwhelmed by Sherlock.

“ _Fuck_ ,” Mycroft swears. He rarely utters oaths but he thinks that might change, and then he stops thinking.

He’s all instinct.

Its instinct when his tongue flicks out and licks the wet toy in Sherlock’s hand, her lips curl into a knowing smirk while her eyes demand more, from him as an alpha, and its instinct when he extends the blade of his tongue and laves the toy so he can savour more of his little sister. He’s growling, almost a purr really, and that’s instinctive too.

Sherlock tosses the toy aside and Mycroft turns to the nearest source of her scent that’s now singing in his blood. His sister, smirking, takes a step backwards and he snaps.


	2. Chapter 2

He lets go of the doorframe and stalks forwards. Sherlock laughs as she bounces on her heels, moving around her large bedroom with light steps and grace; teasing, _taunting_ Mycroft as he chases after her. He grapples with his dressing gown, almost tearing the fine silk fabric as he wrenches it off whilst following his bold, impudent sister. A quick feint and he leaps forward, surprising both himself and a delighted Sherlock as he falls upon her and pushes them both onto her bed.

His fingers dance across her body before he curls his hands around her waist and he pulls her up until she’s settled underneath him. “Took you long enough,” she tells him, as he continues to stroke her creamy skin. “I do hope you’re not _too_ tired out by that little bit of exercise, otherwise you might need to spend more time in your mini-gym,” she taunts.

He pinches her, savours her indignant yelp, before dipping his head to nibble at her collarbone. “You’re far too disrespectful to your elders, my dear,” he chastises between nips.

Sherlock snorts as he worries the skin at the juncture between neck and shoulder. “I do hope ‘elder’ isn’t meant as some sort of code for barely being able to fulfil your part in this.”

“I promise that you’ll have no complaints, sister dear,” Mycroft huffs as he presses his hips down. Already hard and revelling in the friction between their two bodies, his underwear is the only barrier between them and he smirks when Sherlock’s mouth falls open and she inhales sharply.

He stops any further retorts by covering her pretty, bow-shaped lips with his own and kisses her. It quickly turns hot, wet and dirty as they both try to control it. Mycroft shifts his body, rests his weight on his right knee which he presses between Sherlock’s thighs and she immediately rubs her wet pussy against his leg with a low whine.

Mycroft’s been with other omegas before, knows how to enjoy them and make sure they in turn delight in the act but he’s never kept them around for long, never wanted to. Even in this modern age far too many of them were too docile, too subservient for his taste, not to mention how few of them could even remotely hope to interest him intellectually. Sherlock, on the other hand, had grown up without the expectations or demands put upon omegas by society at large, a function of their remote childhood home and upbringing and unless she was in heat, bore no stereotypical traits of most omegas. It was … refreshing.

He brings his hands up to caress the soft, delicate skin around her breasts, teases her nipples until they’re hard. He jumps when he feels Sherlock’s cool, long fingers pull his briefs down and he bucks into them as she starts to touch him. Mycroft can’t hold back a groan, which turns into a low growl, as Sherlock strokes his cock with a firm grasp and he grows harder as he registers just the barest hint of sharp nails. It’s as his sister is pulling at his foreskin, using his pre-come to ease her movement and that _utterly_ clever way she twists her fingers around his cock that he realises she’s done this before, she’s practiced.

Mycroft blinks rapidly as he reminds himself that he already knew that. Logically. Rationally. But he’s so far gone that the thought of Sherlock with another very nearly causes a red haze to overwhelm him. The alpha in him rears its head and he surrenders to it.

Impulsively he drops his head and starts sniffing his sister’s skin, from breast to neck; licks a path from armpit to navel, leaves a path of small bite-marks from her inner thigh to pelvis. He revels in the noises he draws from Sherlock, the little gasps and groans. Each whimper and drag of nails on his own skin drives him on.

_He wants to own Sherlock._

Wants Sherlock to possess him in turn.

The thought should appal him; perhaps it would if any part of him felt brotherly at that very moment but he doesn’t. He is man, lover. Alpha.

His eyes lock onto Sherlock’s and he notes the second that she deduces him, his thoughts, when her lips curl and she snarls, a sound that makes his blood pound harder. Her face, so distinctive with sharp cheekbones, dark lashes framing expressive eyes and full lips, turns wicked and before he realises, she’s wrapped her legs around him and flips them over.

He grunts as he settles back against the mattress, wincing as he pulls a toy from out under his hips and throws it away – Sherlock no longer had any need for that and any other toys still strewn between the sheets. The scrape of nails across his skin, fingers digging into his flesh and sharp tugs at his chest hair pulls his attention to Sherlock. He sees the predatory glint in her eyes and when she shifts her hips they both exhale sharply as she slides across the length of his cock that’s pressed between their bodies.

Mycroft feels the primal urge to bury himself in her, craves it, but more than that, he needs, _wants,_ Sherlock to enjoy it so he deliberately grabs at the bed sheet and lets his sister slide her wet pussy over him. Teases, caresses him. It feels like minutes have gone by as he suffers this exquisite torture but he’s sure that it can have barely exceeded one. He inhales sharply when Sherlock’s weight disappears as she re-positions herself, and an electric shiver runs up his spine as the cool night air hits his cock which is wet from Sherlock’s natural lubrication.

He looks upon her lean, pale form dotted with small, reddening bite-marks he’s left on her skin, her dark hair tumbling and framing her face. He sees his very own Eve, his Siren calling to him. He knows this is her nature, the omega within her and he knows that he is her Adam, the alpha inside him and the fallen man that he is, her mesmerised fool. He has chosen this wilfully and deliberately.

He’s impatient. “Please,” he growls, implores.

He’s rewarded as Sherlock tightens her grip around his cock, holds him at the right angle before she lowers her body. “ _Mycroft_ ,” she breathes as she takes him within her. “Oh my god!”

Mycroft’s too engrossed to immediately reply, to make any sort of recognisable sound. What is left of his great, analytical mind is busy identifying and cataloguing the intense sensations as he slides into Sherlock. There’s pressure, slickness and it’s so _hot_. The feel of her muscles as they grip his cock, caresses him as she takes him in deeper. He wants to say something to express this feeling but his body won’t comply and all that comes out is a series of soft grunts and sighs in counterpoint to Sherlock’s breathy noises.

He immerses himself in the sensations of his sister riding him, lets her take control for the time being; his hands simply caress and hold on to Sherlock’s hips. Her nails dig into his thighs, his chest as she moves upon him, shifting her position as she chases her own pleasure.

The bedroom is filled with the sound of their heavy panting, of slick noises as their bodies slide against each other and Mycroft wants more. He plants his feet into the mattress to give him the leverage he needs and thrusts, meeting Sherlock’s body as she grinds upon him. His pants are drowned out by a long, low keening noise and he wants, _needs_ , to hear more so he does it again and again. A blush creeps along her skin, contrasting against her usual paleness, and their bodies covered with sweat cast a sheen in the dim light.

Mycroft’s never thought about Sherlock in this context before but now his mind can’t help but bring up selected memories, examines options, probe opportunities and calculates probabilities.

First there is the enigma of John Watson, perfectly normal, a doctor, a man who lives life without fear – Mycroft drives his hips up, draws a sharp intake of breath from Sherlock in response – and he’s thankful the good doctor, a beta, is happily married to his lovely wife. Then there was Molly Hooper, another omega and though Mycroft is cognisant – and accepting unlike some others – of omega-omega couples, he knows Sherlock doesn’t recognise Miss Hooper in that way; the other woman fading too easily into the background to be a match for his bright, inquisitive sister.

Then there’s the Detective Inspector from New Scotland Yard, Greg Lestrade, another alpha. _A rival?_ He knows Sherlock respects the man under all her bluff, insults and shields, even if she refuses to remember his name. His hips snap as a wave of jealousy hits him and he delights in how Sherlock’s breathing hitches in turn.

The tendrils of jealousy still cling to him as he bring his right hand to the juncture where their bodies meet, his fingers sliding and searching until he finds her clitoris. He rubs it slowly and watches in fascination, the images of his sister slowly coming undone imprints on his mind.

By his hand, his touch, his demands. _By him and only him._

Mycroft speeds up the snap of his hips, until its almost punishing, focusses all of his attention on building up Sherlock’s impending climax. He varies the speed and pressure against her clit; feels how it swells under his administrations and how the lovely little noises Sherlock makes become harsher, huskier. He grits his teeth, demands his own body obeys his mind and will, to wait, promises it that the delayed gratification will be worth this prolonged period of erotic torture.

He feels, more than hears, Sherlock’s unsteady staccato gulps of air and he presses into her body and _grinds_. He’s instantly aware when her orgasm hits her as her internal muscles clench around him, skin slipping on skin, and her scent becomes more intense. It’s exhilarating and Mycroft’s hips still for a moment, letting her body convulse as he gentles his thumb against her, draws out his sister’s delightful shudders and enchanting moans.

He watches Sherlock, takes in every detail; how she arches her back, her abdominal muscles flexing as she comes and dark locks that stick to dewy skin. Mycroft waits for the right moment to act, when her orgasm starts to wane but not so much that he can’t use it to drive her into a second, more intense, climax when he can finally knot her. He doubts Sherlock’s ever considered such a thing, not when she considers her body as mere transport most of the time.

He can’t wait to look into her eyes when it happens, when she _falls_. To know that he’s the one who can make her feel such intense sensations, that they can take such a hedonistic pleasure in each other and that he’s there to catch her at the end.

_There._ He flips their joined bodies and the sudden change in position leaves him feeling dizzy for a moment but Mycroft quickly gains his bearings and he shifts them both, long limbs tangling together as he sinks back into Sherlock, her legs coming to wrap around him, welcoming him in.

He can still feel the remnants of her first climax as he thrusts into her wet, hot pussy; drives into her relentlessly as he lowers his head to brush his lips against hers in contrast to his brutal movements. He moves to rest his head in the curve of her shoulder, panting into the mess of her hair, his own damp hair starting to curl and blend with her naturally long, dark curls.

He shivers as her fingers trace, scratch, a path from his neck to the base of his spine and he can’t hold back a groan when her fingers dig into his arse, an unspoken command each time he thrusts.

“Mycroft,” his sister whimpers, her voice breaking on the second syllable. “I want to see you.”

He obeys. Although currently relegated in favour of his instincts as an alpha, a hot-blooded male, Mycroft’s greatly admired brain, when operational, can correlate all the times when he’s bowed to Sherlock’s demands and he suspects the calculation would prove that his little sister really has him wrapped around her finger, her wants and needs. That he indulges her should concern him but he’s too captivated by the reflection of desire in her eyes, at how she bites and sucks in her lower lip to try and prevent the moans escaping her as he moves in her but ends up whimpering anyway.

Mycroft’s gut tightens as the last tendrils of control dissipate and he feels his cock start to swell; how steady thrusts into Sherlock lose their rhythm, become wilder, and he once more slips his hand between their bodies and finds Sherlock’s clitoris. He caresses the little nub as he possesses her body, revels in the tremors that haven’t faded since her first climax; his eyes lock onto her blown pupils and he realises he wants to possess her mind too.

Wants her to give herself to him.

She sees his unspoken plea and shivers, her lithe body presses against his own and with the barest hint of a nod he knows she’s placing her trust in him, not just as an alpha but in his ability to satisfy her.

His fingers at her clitoris are wet, slick with her natural lubrication – which is good news as he feels his knot grow, he has no desire to hurt Sherlock – and he increases the circular motion, presses on it more firmly to precipitate Sherlock’s second climax. He looks down upon Sherlock, their foreheads just touching and his breathing is made up of sharp intakes of air and exhales that more resemble growls and grunts.

He snaps his hips several more times. Punishing, deep thrusts, and with the last thrust he drives himself into Sherlock’s hot core, his knot locks them together _and they fall_. Sherlock’s lips part as she lets out a cry – the gorgeous sound interrupted by soft hitches as she tries to inhale much-needed air – and writhes under him, her second orgasm set off as he knotted her. Mycroft holds his sister in his embrace, his lips curl into a genuine smile when her eyes snap to his as she realises that although she is falling – this terrifying feeling of desire, completion and _emotions_ – he’s there to catch her, anchor her in the turbulent storm.

At that moment he realises she is the most breathtakingly beautiful person he knows.

Mycroft’s own orgasm finally hits him and he’s pulsing into Sherlock as he’s assaulted by her inner muscles flexing against his cock, his knot, and it’s all too overwhelming. He tries to process each touch, movement and sound. Commit it all to memory so he can recall each facet at will in the future. There’s a light brush of fingers against his cheek and Mycroft realises he’d closed his eyes. He snaps them open and sees his sister looking back at him, elated, inquisitive and sated.

Realising he’s sprawled on top of her, Mycroft carefully shifts his body until both he and Sherlock are both more comfortable, legs still tangled, mindful that his knot will lock them together for a while longer. He relaxes, feels his sister’s body melt against his, sharing body heat as the cold air creeps in and slumber picks at his consciousness, and he drops a kiss on her damp brow before resting his head on the pillow beneath him.

He feels, rather than sees, Sherlock arch her eyebrow and he’s taken by surprise when she declines to make any comment, choosing to insinuate herself alongside his body – some might even call it cuddling. He’s grateful that Sherlock has chosen not to break their strange new association with words and instead extends an arm to grasp an edge of the duvet and pulls it up, covering their naked bodies. He realises he’s content lying in this bed, Sherlock in his arms, and his face holds a faint hint of a smile when sleep finally reclaims him.

**Author's Note:**

> Posting in two parts because editing is a bitch. Second part is 100% smut I'm afraid :-)


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